Project Summary The present application is in response to Strategy 3.1 of the NIMH strategic plan, which calls for the identification and validation of new targets for treatment development that underlie disease mechanisms. We propose that introspective accuracy (IA) represents a critical novel target for intervention and will therefore meet this goal by comprehensively examining IA in individuals with schizophrenia and individuals with bipolar disorder. Both disorders are characterized by significant social dysfunction, which impairs quality of life and impedes independent living and employment. IA, a term referring to one's ability to evaluate his or her own decisions as correct or incorrect (i.e. to know what one knows and what one does not know), is impaired in individuals with severe mental illness, and our pilot work indicates that impairments in IA are better predictors of functional outcome than are cognitive or functional abilities themselves. This suggests that targeting impaired IA in treatments may lead to improved day-to-day function and quality of life. By assessing IA across the functionally-relevant domains of neurocognition, social cognition, social competence, and functional capacity, we will test the overarching hypotheses that IA is a critical determinant of real-world functioning (Specific Aim 1), that IA is distinct from other forms of self-awareness and uniquely contributes to outcomes (Specific Aim 2), and that within individuals, mood and psychotic symptoms dynamically influence both the degree and direction of introspective deficits (Specific Aim 3). Our study design will allow for the assessment of IA at both inter- and intra-individual levels by utilizing Ecological Momentary Assessment (EMA) to obtain longitudinal data on IA and symptoms. The findings of this project will yield the most thorough understanding of IA to date spanning multiple domains and broadly sampled across two diagnostic constructs. Results will identify a novel treatment target and provide a foundation for the development of psychosocial and neurobiological interventions.